Stuck valve

[Rusty Heaps]

I have a ‘53 straight eight which a previous owner had started apparently after it had been sitting for a while. The number one intake pushrod was incredibly bent ( see pic). After removing the rocker assembly I was able extract the pushrod with a pair of channel locks. The valve was closed. After some soaking with Marvel and P B’laster I tapped the valve in an attempt to free it. Unfortunately it only caused the valve to be stuck in the open position. Nothing I have done has brought the valve back to the closed position or free moving. I soaked it overnight and fogged the inside of the chamber with Seafoam engine fogging oil. Anything else I can do short of pulling the head to free this valve?

[Machine Gun]

I realize that this doesn't answer your question, but I'd pull the head and do a proper inspection, cleaning, whatever. Considering that you didn't free the valve but instead moved it from one stuck position to another it probably needs more attention than you can give it with solvents, mechanical persuasion, and prayers (or curses, depending on your personal philosophy).  Sure, it's a pain dealing with the manifold and the weight of the beast, but you're already partway there with the rocker assembly removed.

[F&J]

2 hours ago, Rusty Heaps said:

I tapped the valve in an attempt to free it

Depends on how hard you had to hit it to move it down.  If you really had to hit it hard all the way down, you may have to pull the head.  If it was light hits, you have a good chance if freeing it up.

 

Your call on pulling the head, but that's a lot of work and buying $$ gaskets for just one stuck valve.

 

Stuck intake is usually from gas turned to varnish, not rust.  Varnish needs something like carb cleaner, lacquer thinner, kerosene, etc.

 

I'd then be trying to make some attachment to hook to the valve retainer and use a slide hammer

 

[F&J]

One thing I'd also try:  If you have a propane torch tip that can fit in the spark plug hole?  That heat will go up through the open valve and heat up the valve guide. 

[edinmass]

Pull the other push rod on that hole, and start and run the car to full temperature. The valve is probably hanging from fuel varnish……the heat will soften it up and it will probably just close on its own. Then replace the push rod. Also, drain the fuel system and use new fuel with no alcohol. It’s not the best option, but the above should break it free…….

[critterpainter]

Another trick is to use vice grips to rotate the valve if it is willing.   I was working on a show quality 48 56C that stuck a valve from sitting.  Of course it was #8 ex valve that was stuck. I "bounced" a small hammer off the valve but it didnt budge even with Kroil helping.  I then tried rotating the valve and it moved just a bit.  light tapping and gentle attempts to rotate it freed it up.   Been running for close to 20 years now.

[Rusty Heaps]

I appreciate all the helpful advice. If I go with the advice to run the engine without the pushrods for the piston of the offending valve is there a possibility of the valve making contact with the piston? I tried small  vise grips, no luck. I believe that in the future I will use a smaller hammer, too.

Edited April 17, 2022 by Rusty Heaps (see edit history)

[EmTee]

1 hour ago, Rusty Heaps said:

...is there a possibility of the valve making contact with the piston?

No, not so long as the valve spring, retainer and its 'keeper' are securely in place.  Once the valve begins to free up, the spring should force it to close.  While warm it would be the time to spray some solvent (e.g., WD-40) at the valve stem.  Once free, normal rocker shaft oil flow should lubricate the guide.

[Rusty Heaps]

I believe it would be prudent to also pull the plug wire to that cylinder, too. I wouldn’t want burnt fuel belching back through the carburetor..